The department within a law enforcement agency which is responsible for dealing with internal issues such as professional misconduct, corruption, etc. (originally more fully "Internal Affairs Bureau", "Internal Affairs Division").
Origin
1940s.
Definition of Internal Affairs in US English:
Internal Affairs
noun
US
The department within a law enforcement agency which is responsible for dealing with internal issues such as professional misconduct, corruption, etc. (originally more fully "Internal Affairs Bureau", "Internal Affairs Division").